Radiator Cap: Inspection

WARNING: This page is about a different variant/trim than selected.

Check that the radiator cap does not have deformation, cracks or damage.
Attach the radiator cap tester to radiator cap.

Courtesy of SUBARU OF AMERICA, INC.
Increase pressure until the radiator cap tester gauge needle stops. Radiator cap is functioning properly if it holds the service limit pressure for 5 - 6 seconds. Replace the radiator cap if its valve opens at less than the service limit.

CAUTION:

Be sure to remove foreign matter and rust from the cap in advance. Otherwise, results of pressure test will be incorrect.
Do not confuse the cap of coolant filler tank and cap of radiator.

Coolant filler tank side:

Standard

93 - 123 kPa (0.95 - 1.25 kg/cm² , 14 - 18 psi)

Limit

83 kPa (0.85 kg/cm² , 12 psi)

Radiator side:

Standard

122 - 152 kPa (1.24 - 1.55 kg/cm² , 18 - 22 psi)

Limit

112 kPa (1.14 kg/cm² , 16 psi)